Warning: PDB altered with errors and PDB_PLUG_IN_VIOLATIONS

If you open your pluggable database and you receive following warning,

SQL> alter pluggable database pdb2 open; Warning: PDB altered with errors.

It would mean that when sync operation of pluggable database was performed while opening it, there was some error and synchronization was not able to complete successfully. Pluggable database would be open, but it will be in restricted mode (as you will see in bellow example). In this case, we should immediately query PDB_PLUG_IN_VIOLATIONS to see what has gone wrong.

ORA-00214: control file version inconsistent with file

If there is a server crash, there could be a possibility that you see ORA-00214 error; once server is up again, and you try to start (mount) the database. Error could be similar to the following.

ORA-00214: control file 'D:\ORACLE\ORADATA\PRODDB\CONTROL02.CTL'
version
857358007 inconsistent with file 'G:\ORACLE\ORADATA\PRODDB\CONTROL01.CTL'
version 857358000

CDB_TABLESPACES not Showing Tablespaces of Pluggable Database

Starting 12c, along with DBA_*, ALL_* and USER_* views, there is another time of data dictionary views available which are CDB_* views. For example, along with DBA_TABLESPACES view there is also CDB_TABLESPACES view. These CDB_* views in a container database show all information of all containers (container + all pluggable databases)

Tablespace Growth History and Forecast for 12c and Above

Finding space usage of tablespaces and database is what many DBAs want to find. In this article I will explain how to find out space usage history and forecasting future growth of tablespaces. For 10g, 11g, you can use Tablespace Growth History and Forecast (10g, 11g) and Database Growth History and Forecast (10g, 11g) scripts.

For 12c container/pluggable Database Growth History and Forecast, see script Database Growth History and Forecast (12c and Above). 

Database Growth History and Forecast for 12c and Above

For 10g, 11g, you can use Tablespace Growth History and Forecast for 10g and 11g and Database Growth History and Forecast for 10g and 11g) scripts.
For 12c and above tablespace growth history and forecast, you can use Tablespace Growth History and Forecast for 12c and Above script.

RMAN Duplicate Database using Live/Active Database

RMAN duplicate command is a very useful automated way to create a copy/clone of a database rather than manually creating a clone of a database. Duplicate database can be created on the same server were source database is running or on a different server. Duplicate database can be created using RMAN backup of source database,

Heartbeat failed to connect to standby. Error is 16009

On one of my 11.2.0.4 dataguard setup on Windows 64 bit, following errors were being reported every minute, in alert log file of standby database.

PING[ARC2]: Heartbeat failed to connect to standby 'proddb'. Error is 16009. Thu Jun 25 07:01:10 2015

ORA-29701: unable to connect to Cluster Synchronization Service

On 11.2.0.3 single server grid infrastructure on Windows 2008, I faced ORA-29701 error while starting ASM instance.

C:\>sqlplus SQL*Plus: Release 11.2.0.3.0 Production on Wed Jun 17 12:44:08 2015

Killing a process using orakill.exe on Windows

If you kill an oracle session using ALTER SYSTEM KILL SESSION command, status of this session in v$session view is set to “KILLED”, and after some time you no longer see this session. Sometimes it may happen that status of this session remains “KILLED” for a very long time and resources taken by this session are still not released. I have observed this especially in

DDL Logging in Oracle

Starting Oracle 12c, DDL (Data Definition Language) command are logged in a log file which is located under <diag_location>/rdbms/<db_unique_name>/<sid>/log. In my case, it is located under c:\app\oracle\diag\rdbms\db12c\db12c\log directory, and log file name is ddl_<db_name>.log. XML version of this DDL log file is stored under